package link.roadio.riff.ui

import link.roadio.riff.indexer.core.media.MediaId

/** Small comparison/navigation input; never contains children or a playback binding. */
data class BrowserRowKey(
    val id: String,
    val label: String,
    val kind: BrowserKind,
    val comparisonName: String = label,
    val genreId: Long? = null,
    val actionTier: Boolean = true,
)

/**
 * A catalog-backed collection. Only get() creates a display row; keys and selections stay flat.
 * AI-INTENT: Equality must not recursively traverse a catalog when Compose compares UI state.
 * https://wiki.271.pics/Riff/1-1-0/catalog-consumption#player-browse-representation
 */
abstract class BrowserRows : AbstractList<BrowserItem>() {
    abstract fun key(index: Int): BrowserRowKey

    open val ready: Boolean get() = true

    open fun prepare() = Unit

    open fun findRow(id: String): BrowserItem? = indices.firstOrNull { rowId(it) == id }?.let(::get)

    open fun rowId(index: Int): String = key(index).id

    open fun mediaId(index: Int): MediaId? = get(index).mediaId

    open fun playable(index: Int): Boolean = get(index).playable

    protected open fun sameRows(other: BrowserRows): Boolean = this === other

    protected open fun rowHash(): Int = System.identityHashCode(this)

    final override fun equals(other: Any?): Boolean = this === other || (other is BrowserRows && sameRows(other))

    final override fun hashCode(): Int = rowHash()
}

internal fun List<BrowserItem>.rowKey(index: Int): BrowserRowKey =
    if (this is BrowserRows) {
        key(index)
    } else {
        get(index).let {
            BrowserRowKey(it.id, it.label, it.kind, it.comparisonName, it.genreId, it.hierarchyUsesActionTier)
        }
    }

internal fun List<BrowserItem>.rowById(id: String): BrowserItem? = if (this is BrowserRows) findRow(id) else firstOrNull { it.id == id }

internal fun List<BrowserItem>.selectRows(indices: IntArray): List<BrowserItem> = SelectedBrowserRows(this, indices)

private class SelectedBrowserRows(
    val source: List<BrowserItem>,
    val selected: IntArray,
) : BrowserRows() {
    override val size get() = selected.size

    override fun key(index: Int) = source.rowKey(selected[index])

    override fun rowId(index: Int) = source.rowId(selected[index])

    override fun mediaId(index: Int) = if (source is BrowserRows) source.mediaId(selected[index]) else source[selected[index]].mediaId

    override fun playable(index: Int) = if (source is BrowserRows) source.playable(selected[index]) else source[selected[index]].playable

    override fun get(index: Int) = source[selected[index]]

    override fun sameRows(other: BrowserRows) =
        other is SelectedBrowserRows && source === other.source && selected.contentEquals(other.selected)

    override fun rowHash() = 31 * System.identityHashCode(source) + selected.contentHashCode()
}

internal fun List<BrowserItem>.projectRows(transform: (BrowserItem) -> BrowserItem): List<BrowserItem> {
    val source = this
    return object : BrowserRows() {
        override val size get() = source.size
        override val ready get() = (source as? BrowserRows)?.ready != false

        override fun prepare() {
            (source as? BrowserRows)?.prepare()
        }

        override fun findRow(id: String) = source.rowById(id)?.let(transform)

        override fun key(index: Int) = source.rowKey(index)

        override fun rowId(index: Int) = source.rowId(index)

        override fun mediaId(index: Int) = if (source is BrowserRows) source.mediaId(index) else source[index].mediaId

        override fun playable(index: Int) = if (source is BrowserRows) source.playable(index) else source[index].playable

        override fun get(index: Int) = transform(source[index])
    }
}

/** Catalog operations used by navigation, queues and AI; none require a recursive UI graph. */
interface BrowserCatalog {
    fun find(id: String): BrowserItem?

    fun tracks(
        contextKey: String,
        playableOnly: Boolean = true,
        ignoreLeadingArticles: Boolean = false,
    ): List<BrowserItem>

    fun track(mediaId: MediaId): BrowserItem?

    fun trackKey(mediaId: MediaId): BrowserRowKey?

    fun preferredBinding(rowId: String): Long?

    fun available(mediaId: MediaId): Boolean

    fun mediaIds(contextKey: String): Set<MediaId>

    fun entities(categoryId: String): List<BrowserMembership>

    fun directoryPaths(): Map<MediaId, List<List<String>>>

    fun trackFacts(): List<BrowserTrackFact>
}

data class BrowserMembership(
    val key: String,
    val mediaIds: Set<MediaId>,
)

data class BrowserTrackFact(
    val mediaId: MediaId,
    val playable: Boolean,
    val reactionKey: String,
    val sourceBindingId: Long? = null,
)

internal fun List<BrowserItem>.rowId(index: Int): String = if (this is BrowserRows) rowId(index) else get(index).id

internal fun List<BrowserItem>.mediaIdsInOrder(): List<MediaId> =
    indices.mapNotNull { index -> if (this is BrowserRows) mediaId(index) else get(index).mediaId }